This invention relates to a method of comparative analysis between historical group data and current analytical data for the purpose of validating the operating accuracy of an instrument. In particular, the invention relates to a method of verifying the operating accuracy of hematology analyzers by comparing current data generated by testing a control substance with historical data collected from a group of similar analyzers testing the same control substance.
Quality control data is generated in the clinical laboratory by causing an analyzer to test known specimens (controls). Such data is typically gathered from a number of instruments all testing the same control substance. The data is then normally subjected to statistical analysis to determine if a particular analyzer is functioning properly, or xe2x80x9cin control,xe2x80x9d prior to testing patient specimens. In many instances, United States federal law mandates daily testing of the analytical system prior to testing specimens from humans. Even when not required by law, daily evaluations of the analytical systems is considered to be proper laboratory practice.
One common method of statistical analysis is based on the mean and standard deviation of the data over time. If new data differs from historical data by a pre-determined statistical variation (e.g., three standard deviations from the mean), the analyzer may be malfunctioning.
Various rules have been developed for conducting a statistical analysis of the data. The so-called Westgard rules normally compare new data from an instrument in a particular laboratory against historical data from that same laboratory. However, analyzing only the data from the same instrument within the same laboratory, rather than from a comparable peer group working with different instruments in different laboratories, can cause a test to suggest an instrument is malfunctioning, when in fact it is not.
Under the Clinical Laboratory Improvement Act of 1988, laboratories testing certain analytes on human specimens are required to participate in a testing program in which a designated agency distributes blind samples to a group of participating laboratories. The results are tabulated and analyzed according to rules specified by government regulation. For example, the grading limits for glucose state that a participant laboratory must have a result falling within 6 mg/dL from the mean of the group or +xe2x88x9210% of the mean of the group, whichever is greatest. The grading limits under the federal regulations are generally more liberal than the Westgard rules because they are based to some degree on clinical significance of allowable error. In addition, the historical data used for comparative analysis is collected from a peer group of different analyzers in different laboratories, which is believed to be more reliable information than that selected from a single analyzer.
An inter-laboratory quality assurance program is disclosed in U.S. Pat. No. 4,858,154, which is incorporated herein by reference. Prior art systems for doing comparative analysis on inter-laboratory data have relied upon electronic data input from a number of laboratories to a central computer where the data is analyzed and a report is sent to the participating laboratory in either electronic or hard-copy form. The shortcomings of these prior art systems include the fact that there is normally a delay of anywhere from several days to weeks to obtain a report from the data processing center. By the time the report is received and there is an indication of malfunction of a particular analyzer, hundreds or thousands of specimens may have already been processed. Heretofore, there has been no procedure for a participating laboratory to input data and then synchronize their data with the historical data prior to analysis. It has also heretofore not been possible to obtain real time analysis to permit the laboratory to make an immediate determination of the reliability of a particular instrument.
A further shortcoming of the prior art has been that the participating laboratory which is coupled with a central data repository to select the most appropriate category of data for comparative analysis. For example, in some instances it may be preferable to make a comparative analysis with instruments in a particular geographic region, while in other instances it may be desirable to do the comparative analysis based upon a particular instrument model.
It is therefore an object of the present invention to allow analysis of an instrument based on the federal regulations or the Westgard Rules for evaluating the data on an on-demand, rather than a periodic, basis.
It is therefore an object of the present invention to provide a method of evaluating the performance of an instrument by comparing operating data with historical data whereby the current data can be input to a global database prior to making the comparative analysis.
Another objective of this invention is to provide a method for evaluating the performance of an instrument by comparing operating data with historical data whereby the historical data may be accessed and retrieved prior to conducting the comparative analysis.
Another very important object of the invention is to provide a procedure for evaluating instrument performance by comparing operating data with historical data whereby the historical data is grouped into categories for comparative analysis and the evaluation procedure may include selecting a particular group of data for comparative analysis purposes.
Another one of the aims of the present invention is to provide a procedure for evaluating the performance of an instrument, particularly a hematology analyzer, wherein all of the procedural features set forth in the foregoing objectives are available instantaneously in real time by any participating laboratory.
Still another one of the objects of the invention is to provide a method of evaluating the performance of an instrument as set forth in the aims and objects preceding wherein each participating laboratory may communicate directly with the repository so that the historical database is continuously updated.
To accomplish these and other objectives, a user preferably begins by conducting an operation on a desired instrument and obtaining individual data from this operation. The user then stores the individual data in a client database on a client computer, such as a PC. The user also preferably stores in the client database rules for analyzing the data and a report capability to display the results of such analysis. The client computer is provided with a capability for transferring data, such as a modem providing access to the Internet, to exchange data with a global database on a server computer. Alternatively, such data transfer between the client database and the global database could occur via a diskette. The global database contains data generated by conducting a substantially identical operation on a group of like instruments.
The user selects desired attributes and the desired group data and then synchronizes to a desired extent the data in the client database with the data obtained from the global database. During synchronization, the data from the operation is transferred to a global database. Similarly, the local database can accept data from the global database corresponding to the user""s selected instrument(s).
After synchronization, the local client database contains current statistical data concerning the peer-groups in which the laboratory is participating and other peer-groups of interest to the user. Using the client database, the user can then immediately perform desired statistical analyses, among other reasons, to set the group mean for analysis of the daily that data in accordance with federal regulations.